21187130753 has 18 divisors (see below), whose sum is σ = 22995281862. Its totient is φ = 19453365120.

The previous prime is 21187130747. The next prime is 21187130771. The reversal of 21187130753 is 35703178112.

It can be written as a sum of positive squares in 3 ways, for example, as 1908641344 + 19278489409 = 43688^2 + 138847^2 .

It is not a de Polignac number, because 21187130753 - 2⁴ = 21187130737 is a prime.

It is a super-3 number, since 3×21187130753³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21187130773) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 25806083 + ... + 25806903.

It is an arithmetic number, because the mean of its divisors is an integer number (1277515659).

Almost surely, 2^21187130753 is an apocalyptic number.

It is an amenable number.

21187130753 is a deficient number, since it is larger than the sum of its proper divisors (1808151109).

21187130753 is an frugal number, since it uses more digits than its factorization.

21187130753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1745 (or 881 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 38.

The spelling of 21187130753 in words is "twenty-one billion, one hundred eighty-seven million, one hundred thirty thousand, seven hundred fifty-three".